In general, when one end of a pipe is welded, a welding portion located on a circumference of the pipe is welded using a welding torch.
However, in a case where a welding apparatus having a regular mechanism rather than a hand-operated welding machine, which is used in a state of being directly held by a worker, is used, a disposition position of the pipe and torch should be correctly arranged so that correct welding can be performed.
In particular, in a case where a welding operation is performed with rotation of the pipe which is an operation member of a welding apparatus fixedly installed in a specific operation area, a regular instrumental position relationship between the torch of the welding apparatus and a welding line of the pipe should be confirmed and a certain posture should be maintained. However, it is problematic that there is no appropriate apparatus to realize it.